Can't save network connections after editing (DNSCrypt)

I'm trying to setup DNSCrypt on Xubuntu 20.04.4. I've actually had it done once, just a few minutes ago, but I removed it when I was double checking it was functioning correctly.

Now as I try to restore the settings, I'm unable to save them:

I remember I had some problems saving the settings when I first tried it, but after clicking around it became available. I can't remember exactly what I did though and I can't repeat it.

Whenever I change IPv4 to 'manual' the save button greys out. I see this has been a bug since 2011

I had the settings exactly as shown in the screenshot before and I was able to save it, somehow.

I've tried the invisible entries fix to no avail, and also hitting 'Enter' or 'Tab' but none of this works.

I was doing something with editing and deleting the 'Addresses' section previously, when I noticed 'save' became available. I've tried to repeat it, but I'm unable.

Anyone know how to solve this?